Cassini Scientists Rethinking Titan

NASA and the European Space Agency became fascinated with Saturn's moon, Titan, after analyzing the data from Voyager's flyby in 1980 and 1981. That's when they discovered the moon's dense atmosphere, made mostly of methane. Why, they wondered, at temperatures prevalent on Titan, doesn't the methane fall from the sky like rain? Perhaps there was a ocean of methane on the surface.

So they decided to launch Cassini-Huygens at a cost of $3.27 billion. But instead of answers, researchers are finding fuel for more and more questions.

For instance:

Even though the Titan telemetry from Cassini isn't quite what scientists were hoping for, they're seeing lines that could indicate cracks in the ice covering the surface. That could be a sign that Titan is all shook up by quakes -- meaning the Saturnian moon is a lot more geologically active than first believed.

Dark-hued plateaus once thought to be covered in a sort of carbon-based tar appear instead to be covered with ice.

Light-colored plateaus once thought to be made up of ice or liquid methane are instead a mixture of water and carbon-tar.

In spots where the plateaus butt up against each other, lines that should appear sharp -- as they do on Ganymede -- are instead fuzzy. Ellis Miner at the Jet Propulsion Lab in Pasadena (CA) tells USA Today, "I think the fuzziness we've seen so far is telling us something is going on down there."

There are very few craters pockmarking Titan's surface. That leads scientists to theorize that impacts are quickly covered up by wind or perhaps even some sort of icy volcanos.

"I think there's more surprise than disappointment," Miner tells USA Today. "We're going to see some really fascinating things."

Elizabeth Tuttle, a University of Arizona scientist on the Cassini imaging team, agrees. "The story has changed completely," she told the national newspaper.

Tuttle, Miner and other scientists expect more answers in January. That's when Cassini will pass within 746 miles of Titan and release a drop-ship, the Huygens lander. Combined data from both vehicles is expected to clear up a lot of things about Saturn's most fascinating moon -- but, as with the mission so far, it could also raise more questions.

FMI: http://saturn.jpl.nasa.gov/index.cfm